Microfluidic chip and reagent pre-storage method thereof

Abstract

The present invention provides a microfluidic chip and a reagent pre-storage method thereof, wherein the microfluidic chip comprises a substrate, a liquid storage cavity is provided on the substrate, and the liquid storage cavity is connected to a liquid channel; a first liquid insulator is arranged in the liquid storage cavity, and a reagent is formed in the first liquid insulator; a liquid flow port is formed between the liquid storage cavity and the liquid channel, a second liquid insulator is arranged in the liquid flow port, and a second liquid insulator is also arranged at the sample addition port of the liquid storage cavity, and the melting point of the second liquid insulator is higher than the melting point of the first liquid insulator. The method comprises injecting the first liquid insulator into the liquid storage cavity of the microfluidic chip, and injecting the reagent into the liquid storage cavity; injecting the second liquid insulator into the liquid flow port between the liquid storage cavity and the liquid channel, and injecting the second liquid insulator at the sample addition port of the liquid storage cavity, and the melting point of the second liquid insulator is higher than the melting point of the first liquid insulator. The present invention can conveniently realize the pre-storage of reagents and reduce the use cost of the microfluidic chip.

Description

Technical Field

[0001] The present invention relates to the technical field of nucleic acid detection, and in particular to a microfluidic chip and a reagent pre-storage method for the microfluidic chip. Background Art

[0002] Nucleic acid detection is an important means of virus detection. The existing nucleic acid detection method is to obtain the sample, lyse, elute, wash and other operations in sequence, and then put the sample into the reaction solution for amplification reaction. However, the existing nucleic acid extraction operation is mostly based on a kit and is performed manually. It needs to be performed in a special extraction laboratory and the operation of the operator is very cumbersome, resulting in low efficiency of nucleic acid extraction, which affects the efficiency of virus detection.

[0003] A microfluidic chip is a device that can efficiently detect nucleic acids. Multiple electrodes are set in the microfluidic chip. By applying voltage to the electrodes, the liquid in the chip flows, thereby realizing operations such as sample lysis, elution, and cleaning, which can greatly improve the efficiency of nucleic acid detection. Therefore, it is usually necessary to store a variety of reagents in the microfluidic chip. For example, multiple liquid storage chambers are set in the microfluidic chip, and each liquid storage chamber stores a reagent, such as a lysis solution, a cleaning solution, an elution solution, etc. Before nucleic acid detection is performed, the reagents in each liquid storage chamber should not be released. When performing nucleic acid detection, the reagents in the liquid storage chamber need to be released so that the reagents can move on the electrodes.

[0004] Most of the existing microfluidic chips use vesicles or reagent tubes to pre-store reagents. When the reagent needs to be released, it is usually necessary to cooperate with a mechanical structure. For example, the invention patent application with publication number CN110208528A discloses a microfluidic chip, which includes a substrate provided with a sealed storage portion and a magnetic bead mixture installed in the sealed storage portion. The magnetic bead mixture includes magnetic bead particles, thermoreversible gel and a mixed solution. By changing the temperature, under the action of the thermoreversible gel, the magnetic bead mixture realizes liquid and gel state switching. In addition, the sealed storage portion is provided with a weak portion, and a channel connected to the weak portion is provided on the substrate. When using a microfluidic chip for nucleic acid detection, it is necessary to squeeze the sealed storage portion to break the weak portion, and heat the magnetic bead mixture so that the liquid magnetic bead mixture flows from the weak portion to the channel and reaches the reaction area through the channel.

[0005] However, since this microfluidic chip uses a vesicle-like method to store the magnetic bead mixture, it is necessary to apply pressure to the sealed storage part to rupture the weak part during use. If a dedicated device is used to squeeze the sealed storage part, the use cost of the microfluidic chip will increase. If the sealed storage part is squeezed manually, it is easy to apply too much or too little pressure. If the pressure is large enough, it will easily damage the entire microfluidic chip. If the pressure is too small, the magnetic bead mixture cannot be completely released, resulting in a low success rate of reagent release, which affects the use of the microfluidic chip. Summary of the invention

[0006] The first object of the present invention is to provide a microfluidic chip that can pre-store reagents and is easy to use.

[0007] The second object of the present invention is to provide a method for pre-storing reagents in the above-mentioned microfluidic chip.

[0008] To achieve the first purpose of the present invention, the microfluidic chip provided by the present invention includes a substrate, at least one liquid storage cavity is provided on the substrate, and the liquid storage cavity is connected to the liquid channel; a first liquid insulator is arranged in the liquid storage cavity, and the reagent is formed in the first liquid insulator; and a liquid flow port is formed between the liquid storage cavity and the liquid channel, a second liquid insulator is arranged in the liquid flow port, and a second liquid insulator is also provided at the sample addition port of the liquid storage cavity, and the melting point of the second liquid insulator is higher than the melting point of the first liquid insulator.

[0009] It can be seen from the above scheme that the sample addition port and the liquid flow port of the liquid storage cavity are sealed with the second liquid insulator. Since the melting point of the second liquid insulator is relatively high, the second liquid insulator of the microfluidic chip remains solid at room temperature, thereby sealing the reagent in the liquid storage cavity. When the microfluidic chip is used for nucleic acid detection, it is only necessary to heat the second liquid insulator and melt it. Since the melting point of the first liquid insulator is relatively low, when the second liquid insulator melts, the first liquid insulator has also melted. In this way, the reagent can pass through the liquid flow port and flow into the liquid channel.

[0010] It can be seen that the reagent release process only requires heating the second liquid insulator, and does not require the help of external equipment or manual squeezing and other operations. While not increasing the cost of using the microfluidic chip, there will be no problem of excessive or insufficient artificial pressure. It only needs to control the heating temperature to time the release of the reagent. The microfluidic chip is very convenient to use and will not cause damage to the microfluidic chip.

[0011] A preferred solution is that a first liquid insulator is also arranged in the liquid channel. Since the first liquid insulator in the liquid storage cavity can wrap the reagent to form a reagent storage space, when the reagent flows in the liquid channel, the first liquid insulator in the liquid channel can effectively separate the reagents in different liquid storage cavities, thereby preventing the reagents in different liquid storage cavities from mixing and affecting the accuracy of the detection.

[0012] A further solution is that a heating device is provided in the substrate, and the heating device is located directly below the liquid flow port.

[0013] It can be seen that the second liquid insulator located directly above the liquid flow port can be quickly melted by the heater. Since the second liquid insulator located at the sample addition port is far away from the heater and is not easy to melt, the problem of the second liquid insulator located at the sample addition port melting and causing the reagent to flow out of the sample addition port can be avoided during the heating process of the heater.

[0014] In a further embodiment, the first liquid insulator is paraffin oil with a first melting point, and the second liquid insulator is paraffin oil with a second melting point. Preferably, the melting point of the second liquid insulator is higher than 50°C, and the melting point of the first liquid insulator is lower than 35°C.

[0015] Since the components of paraffin oil can be configured according to actual needs, paraffin oil with different melting points can be obtained by changing the ratio of different components in paraffin oil, so paraffin oil with different melting points can be obtained at low cost. In addition, since the melting point of the second liquid insulator is higher than 50°C, it can remain solid at room temperature, which is conducive to the storage and transportation of the microfluidic chip at room temperature.

[0016] To achieve the second purpose of the present invention, the reagent pre-storage method of the microfluidic chip provided by the present invention can be applied to the above-mentioned microfluidic chip, the method comprising injecting a first liquid insulator into the liquid storage cavity of the microfluidic chip, and injecting a reagent into the liquid storage cavity, the reagent being wrapped by the first liquid insulator; and, injecting a second liquid insulator into the liquid flow port between the liquid storage cavity and the liquid channel, and injecting a second liquid insulator at the sample addition port of the liquid storage cavity, the melting point of the second liquid insulator being higher than the melting point of the first liquid insulator.

[0017] It can be seen from the above scheme that the reagent is injected into the liquid storage cavity to which the first liquid insulator has been added, and the reagent can be wrapped by the space surrounded by the first liquid insulator, thereby forming a space for storing the reagent. In addition, the first liquid insulator and the reagent can be sealed in the liquid storage cavity by the second liquid insulator, thereby realizing the pre-storage of the reagent. When using a microfluidic chip, it is only necessary to heat the substrate to melt the second liquid insulator, and the reagent can flow out of the liquid storage cavity. There is no need to use special tools or manual extrusion to release the reagent, which facilitates the use of the microfluidic chip, can also reduce the cost of using the microfluidic chip, and can also ensure a high success rate of reagent release.

[0018] A preferred solution is that when the first liquid spacer is injected into the liquid storage chamber, the first liquid spacer is also injected into the liquid channel.

[0019] Since the first liquid insulator is injected into the liquid channel, it is possible to prevent reagents in different liquid storage chambers from mixing with each other through the liquid channel, thereby ensuring the purity of the reagents in each liquid storage chamber and improving the accuracy of nucleic acid detection.

[0020] A further solution is to store the microfluidic chip at a temperature lower than the melting point of the first liquid insulator after injecting the second liquid insulator into the sample injection port.

[0021] In this way, it can be ensured that the first liquid insulator and the second liquid insulator are both preserved in a solid state, thereby preventing the reagent from flowing out of the liquid storage cavity.

[0022] A further solution is that when the microfluidic chip is used for detection, a heater arranged directly below the liquid flow port is used to heat and melt the second liquid insulator.

[0023] A further solution is to melt the second liquid insulator located at the liquid flow port and then perform electrowetting treatment on the electrodes on the substrate to drive the reagent to move on the electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Structural diagram of a microfluidic chip embodiment of the present invention.

[0025] Figure 2 Structural exploded view of an embodiment of the microfluidic chip of the present invention.

[0026] Figure 3 4 is a cross-sectional view of an embodiment of a microfluidic chip of the present invention.

[0027] Figure 4 It is a flow chart of an embodiment of a method for pre-storing reagents in a microfluidic chip according to the present invention.

[0028] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0029] The microfluidic chip of the present invention can store one or more reagents in advance, and can realize automatic extraction of nucleic acids in samples, for example, guiding the extracted nucleic acids to the amplification reaction area to perform nucleic acid amplification reaction. The microfluidic chip of the present invention can realize automatic release of reagents, does not require special equipment or manual squeezing to release the reagents, can reduce the use cost of the microfluidic chip, and can also ensure the success rate of reagent release.

[0030] See also Figure 1 and Figure 2 The microfluidic chip of this embodiment has a substrate, which includes a circuit board 10 and a cover plate 20. A mounting frame 31 is arranged between the circuit board 10 and the cover plate 20. The lysis pool cover 30 can be snapped onto the mounting frame 31 and fixed on the circuit board 10. In this way, the lysis pool cover 30, the mounting frame 31 and the circuit board 10 form a lysis pool with an open upper end.

[0031] A plurality of electrodes 11 are arranged on the circuit board 10, and a connection port 15 is arranged at one end of the circuit board 10, and the connection port 15 can contact with an external electrical connection terminal and obtain electrical energy, and each electrode 11 can be individually controlled, for example, a voltage is applied, so as to achieve electrowetting treatment for each electrode 11. When an electrode 11 is electrowetting treated, the liquid flowing through the electrode 11 can be attracted to move in a preset direction, or be fixed on the electrode 11, so as to achieve the flow of liquid on the circuit board 10.

[0032] The microfluidic chip is provided with a plurality of liquid storage chambers, for example, a cleaning chamber 21, an elution chamber 22 and a reaction liquid chamber 23, each of which stores a reagent, for example, a cleaning liquid is stored in the cleaning chamber 21, an elution liquid is stored in the elution chamber 22, and a reaction liquid is stored in the reaction liquid chamber 23. In addition, a first nucleic acid amplification reaction chamber 24 is formed on the cover plate 20, and preferably, the first nucleic acid amplification reaction chamber 24 is a region for performing PCR nucleic acid amplification reaction. In addition, the sample injection ports of each liquid storage chamber are formed on the cover plate 20 away from the circuit board 10, for example, a cleaning liquid injection port 25 of the cleaning chamber 21, an elution liquid injection port 26 of the elution chamber 22, a reaction liquid injection port 27 of the reaction liquid chamber 23 and a liquid injection port 28 of the first nucleic acid amplification reaction chamber 24 are formed on the outer surface of the cover plate 20. Further, a hydrophobic coating is provided on the surface of the cover plate 20 close to the circuit board 10, which is conducive to the movement of liquid between the circuit board 10 and the cover plate 20.

[0033] The microfluidic chip of this embodiment can be used to implement LAMP nucleic acid amplification reaction or QPCR nucleic acid amplification reaction. Therefore, a second nucleic acid amplification reaction area 29 is formed on the circuit board 10, and a plurality of detection electrodes 18 are arranged on the second nucleic acid amplification reaction area 29. The reagent can be guided to the detection electrode 18 through the electrode 11 to perform a secondary nucleic acid amplification reaction.

[0034] In this embodiment, the corresponding reagents are pre-stored in each liquid storage cavity. Before nucleic acid detection, for example, during the storage and transportation of the microfluidic chip, it is necessary to ensure that the reagents in each liquid storage cavity do not flow to each other and cause mutual mixing, thereby ensuring the purity of the reagents in each liquid storage cavity. When performing nucleic acid detection, it is necessary to allow the reagents in each liquid storage cavity to flow out, for example, to flow to the liquid channel between the circuit board 10 and the cover plate 20, and by applying a voltage to the electrode 11, the liquid can flow in a preset direction to achieve operations such as sample lysis, cleaning, and elution.

[0035] To this end, this embodiment uses liquid insulators to seal the reagents. Specifically, two liquid insulators with different melting points are used to seal the reagents, wherein the first liquid insulator has a lower melting point and the second liquid insulator has a higher melting point. The first liquid insulator is filled in the liquid storage cavity and the liquid channel, mainly to provide storage space for the reagents, and the second liquid insulator is used to seal the liquid storage cavity to prevent the reagents from flowing out of the liquid storage cavity.

[0036] Take the cleaning chamber 21 as an example below. Figure 3 The pre-storage structure of the reagent is introduced in detail. A liquid channel 35 is formed between the circuit board 10 and the cover plate 20, the cleaning chamber 21 is connected to the liquid channel 35, and a liquid communication port 36 is formed at the connection point between the cleaning chamber 21 and the liquid channel 35. A cleaning liquid 40 as a reagent is stored in the cleaning chamber 21. In this embodiment, the cleaning liquid 40 is wrapped by a first liquid insulator 41. Since the cleaning liquid 40 is in an aqueous phase and the first liquid insulator 41 is in an oil phase, the cleaning liquid 40 does not dissolve in the first liquid insulator 41, but is wrapped in the first liquid insulator 41.

[0037] Preferably, the first liquid insulator 41 is solid at room temperature, that is, the melting point of the first liquid insulator 41 is higher than 25°C, so that when the microfluidic chip is stored at room temperature, the cleaning liquid 40 will not flow out of the cleaning chamber 21. In addition, the first liquid insulator 41 is solid at room temperature, forming a storage space for the cleaning liquid 40, so that the cleaning liquid 40 is not dispersed in the entire cleaning chamber 21, but is wrapped by the first liquid insulator 41. When making a microfluidic chip, the first liquid insulator 41 is first injected into the cleaning chamber 21, and then a certain amount of cleaning liquid 40 is injected according to the needs of use. In this way, regardless of the volume of the injected cleaning liquid 40, the cleaning liquid 40 will be wrapped by the first liquid insulator 41. Therefore, the solidified first liquid insulator 41 actually forms a storage capsule for the cleaning liquid 40.

[0038] It can be seen that the volume of the cleaning liquid 40 can be injected according to actual needs. Similarly, other liquid storage chambers can also be injected with corresponding volumes of reagents according to actual needs, that is, the injection volume of various reagents is completely determined according to actual needs. Without changing the volume of each liquid storage chamber, the appropriate volume of reagents can be flexibly injected, so that a microfluidic chip can meet the requirements of reagent volume of multiple different specifications. There is no need to develop microfluidic chips with specific liquid storage chamber specifications according to the reagent volume requirements of different reagents, which improves the versatility of the microfluidic chip and reduces the production cost of the microfluidic chip.

[0039] When using a microfluidic chip for nucleic acid detection, the cleaning liquid 40 needs to flow in the liquid channel 35. However, before nucleic acid detection is performed, it must be ensured that the cleaning liquid 40 does not flow out of the cleaning chamber 21. To this end, this embodiment uses a second liquid insulator with a higher melting point to seal the cleaning chamber 21. Figure 3 It can be seen that a second liquid insulator 44 is disposed at the liquid communication port 36 between the cleaning chamber 21 and the liquid channel 35 , and a second liquid insulator 43 is also disposed at the sample addition port 25 of the cleaning chamber 21 .

[0040] In this embodiment, the second liquid insulators 43 and 44 have a relatively high melting point, for example, a melting point of more than 50° C., and further, a melting point of more than 65° C. Thus, at room temperature, the second liquid insulators 43 and 44 are not easily melted, thereby sealing the cleaning liquid 40 and the first liquid insulator 41 in the cleaning chamber 21 .

[0041] Since the liquid channel 35 is connected to a plurality of different liquid storage chambers, such as the cleaning chamber 21 and the elution chamber 22, in order to prevent the cleaning liquid 40 and the elution liquid from flowing in the liquid channel 35 before nucleic acid detection, the channel is also filled with a first liquid insulator 42. Preferably, the melting point of the first liquid insulator 42 is the same as that of the first liquid insulator 41, both higher than 25°C, but lower than the melting points of the second liquid insulators 43 and 44. For example, the melting points of the first liquid insulators 41 and 42 are not higher than 35°C.

[0042] Specifically, the first liquid insulators 41, 42 and the second liquid insulators 43, 44 are all paraffin oil, but the specific components of the paraffin oil are different, or the ratios of the various components are different. Since paraffin oil is a mixture of multiple alkanes, paraffin oils with different melting points can be obtained by changing the ratios of the various components. This embodiment utilizes this property of paraffin oil to produce the first liquid insulators 41, 42 and the second liquid insulators 43, 44 with different melting points.

[0043] A heater is provided in the circuit board 10, for example, a heating wire 45 is provided. Preferably, the circuit board 10 is a multi-layer circuit board, and the heating wire 45 is provided on at least one layer of the circuit board. In addition, the heating wire 45 is located directly below the liquid communication port 36. By energizing the heating wire 45, the temperature of the heating wire 45 can be increased, thereby increasing the temperature of the second liquid insulator 44 at the liquid communication port 36. When the temperature of the second liquid insulator 44 exceeds its melting point, the second liquid insulator 44 is converted from a solid state to a liquid state. Since the melting points of the first liquid insulators 41 and 42 are both lower than the melting point of the second liquid insulator 44, when the second liquid insulator 44 melts, the first liquid insulators 41 and 42 are already melted. At this time, the melted first liquid insulator 41 can flow into the liquid channel 35. Since the cleaning liquid 40 is in an aqueous phase, and the first liquid insulators 41 and 42 are in an oil phase, the cleaning liquid 40 will not dissolve in the first liquid insulators 41 and 42. In this way, by applying a voltage to the electrode 11 , the cleaning liquid 40 is driven to flow in the liquid channel 35 .

[0044] In addition, since the distance between the second liquid insulator 43 and the heating wire 45 at the sample injection port 25 is relatively far, and there is also the cleaning liquid 40 and the first liquid insulator 41 between the second liquid insulator 43 and the heating wire 45, the heat transferred to the second liquid insulator 43 is relatively small, and even if the second liquid insulator 44 reaches the melting temperature, the second liquid insulator 43 is still not melted. Therefore, by reasonably controlling the temperature of the heating wire 45, it can be ensured that the second liquid insulator 44 melts, but the second liquid insulator 43 does not melt, thereby preventing the cleaning liquid 40 from flowing out of the sample injection port 25 during the nucleic acid detection process, and preventing the external liquid from entering the cleaning chamber 21 through the sample injection port 25 to cause the cleaning liquid 40 to be contaminated.

[0045] Combine the following Figure 4 A method for pre-storing reagents in a microfluidic chip is introduced. First, step S1 is performed to inject a first liquid insulator 42 into the liquid channel 35, for example, injecting the first liquid insulator 42 into the liquid channel 35 through the sample injection port 25. Since the first liquid insulator 42 is paraffin oil, which has a certain viscosity, under the action of surface tension, the first liquid insulator 42 flows slowly in the liquid channel 35 and does not flow into the liquid storage cavity all at once.

[0046] Then, step S2 is executed to inject the second liquid insulator 44 into the liquid circulation port 36, for example, the second liquid insulator 44 is injected into the liquid circulation port 36 through the sample injection port 25. Since the second liquid insulator 44 has a high melting point, after the second liquid insulator 44 is injected, the microfluidic chip is placed in an environment lower than the melting point of the second liquid insulator 44, so that the second liquid insulator 44 can solidify in a short time, thereby sealing the first liquid insulator 42 in the liquid channel 35.

[0047] Next, step S3 is performed to inject a first liquid insulator into the liquid storage cavity, for example, inject a first liquid insulator 41 into the cleaning cavity 21. Preferably, the first liquid insulator 41 is injected into the cleaning cavity 21 through the sample injection port 25. For example, the microfluidic chip is placed at a temperature higher than the melting point of the first liquid insulator 41 but lower than the melting point of the second liquid insulator 44, and the first liquid insulator 41 is injected into the cleaning cavity 21, so that the first liquid insulator 41 remains in a liquid state in the cleaning cavity 21.

[0048] Then, step S4 is performed to inject the reagent into the liquid storage cavity, for example, inject the cleaning liquid 40 into the cleaning cavity 21 that has been filled with the first liquid insulator 41. Since the cleaning liquid 40 will not dissolve in the first liquid insulator 41, the cleaning liquid 40 injected into the cleaning cavity 21 can be wrapped by the first liquid insulator 41. Preferably, a syringe is inserted into the first liquid insulator 41 and the cleaning liquid 40 is injected, so that the cleaning liquid 40 is completely located in the first liquid insulator 41. In addition, step S4 needs to be performed at a temperature higher than the melting point of the first liquid insulator 41, for example, the microfluidic chip is placed on an operating table above 35°C.

[0049] Next, step S5 is executed to inject the second liquid insulator 43 at the sample injection port 25, and step S6 is quickly executed to store the microfluidic chip in a low-temperature environment, so that the injected second liquid insulator 43 can solidify quickly and seal the liquid storage cavity, and the reagents in the liquid storage cavity and the first liquid insulator 41 will not flow out of the liquid storage cavity. The low-temperature environment in step S6 is an environment lower than the melting point of the first liquid insulator 41. Preferably, the microfluidic chip can be stored in an environment lower than 10°C, and further, stored in an environment of 4°C to 8°C. In this way, the first liquid insulators 41, 42 and the second liquid insulators 43, 44 are all in solid state, and the cleaning liquid 40 and other reagents are all sealed in the liquid storage cavity.

[0050] Since the second liquid insulators 43 and 44 have a high melting point, they will not melt when stored or transported at room temperature. Therefore, the microfluidic chip can be stored or transported at room temperature and does not need to be stored or transported at a specific low temperature, which can reduce the storage and transportation costs of the microfluidic chip.

[0051] When using a microfluidic chip for nucleic acid detection, after placing the sample in the lysis pool, current is applied to the heating wire 45, so that the heating wire 45 generates heat and melts the second liquid insulator 44. Since the first liquid insulators 41 and 42 have a lower melting point, when the local heating wire 45 is powered on, the first liquid insulators 41 and 42 melt first. When the second liquid insulator 44 melts, the cleaning liquid 40 and other reagents can flow into the liquid channel 35 through the liquid flow port 36. Since the second liquid insulator 43 located at the sample injection port 25 is far away from the heating wire 45, the second liquid insulator 43 can be prevented from melting by controlling the temperature of the heating wire 45. In this way, the sample injection port 25 is always kept sealed during the nucleic acid detection process, thereby preventing external contaminants from entering the liquid storage cavity.

[0052] After the reagent flows to the liquid channel 35, the electrode 11 is subjected to electrowetting treatment, that is, by applying current to the electrode on the circuit board 10 and driving the reagent to flow in a specific direction, automatic detection of the sample is achieved. For example, the sample is subjected to an amplification reaction after lysis, washing, elution and other steps, so as to obtain the final detection result based on the result of the amplification reaction.

[0053] The present invention utilizes two liquid insulators with different melting points to seal the reagent, and in particular utilizes a second liquid insulator with a higher melting point to seal the reagent in a liquid storage cavity. When using a microfluidic chip for detection, it is only necessary to melt the first liquid insulator and the second liquid insulator by heating the heating wire, without the need for special equipment or manual extrusion of vesicles, and the temperature of the heating wire can be flexibly and simply controlled, for example, by controlling the current loaded into the heating wire, the power-on time, etc., so as to ensure that the reagent can flow smoothly into the liquid channel, improve the success rate of reagent release, and reduce the use cost of the microfluidic chip.

[0054] Finally, it should be emphasized that the present invention is not limited to the above-mentioned embodiments. For example, changes in the specific structure of the microfluidic chip, or changes in the melting point of the liquid insulator, changes in the composition of the paraffin oil, etc., should also be included in the scope of protection of the claims of the present invention.

Claims

1. A microfluidic chip, comprising: A substrate, wherein at least one liquid storage cavity is disposed on the substrate, and the liquid storage cavity is communicated with the liquid channel; A first liquid insulator is arranged in the liquid storage cavity, and the reagent is formed in the first liquid insulator; Features: A liquid flow port is formed between the liquid storage cavity and the liquid channel, and a second liquid insulator is arranged at the liquid flow port. The second liquid insulator is also arranged at the sample addition port of the liquid storage cavity, and the melting point of the second liquid insulator is higher than that of the first liquid insulator.

2. The microfluidic chip according to claim 1, characterized in that: The first liquid insulator is also arranged in the liquid channel.

3. The microfluidic chip according to claim 1 or 2, characterized in that: A heating device is arranged in the substrate, and the heating device is located directly below the liquid flow port.

4. The microfluidic chip according to claim 1 or 2, characterized in that: The first liquid insulator is paraffin oil with a first melting point, and the second liquid insulator is paraffin oil with a second melting point.

5. The microfluidic chip according to claim 1 or 2, characterized in that: The melting point of the second liquid insulator is higher than 50°C, and the melting point of the first liquid insulator is lower than 35°C.

6. A reagent pre-storage method for a microfluidic chip, wherein a liquid storage cavity and a liquid channel are formed on a substrate of the microfluidic chip, the method comprising: Injecting a first liquid insulator into a liquid storage cavity of a microfluidic chip, and injecting a reagent into the liquid storage cavity, wherein the reagent is wrapped by the first liquid insulator; Features: A second liquid insulator is injected into the liquid flow port between the liquid storage chamber and the liquid channel, and the second liquid insulator is injected into the sample injection port of the liquid storage chamber, wherein the melting point of the second liquid insulator is higher than the melting point of the first liquid insulator.

7. The reagent pre-storage method for a microfluidic chip according to claim 6, characterized in that: Before injecting the first liquid insulator into the liquid storage chamber, injecting the first liquid insulator into the liquid channel.

8. The reagent pre-storage method for a microfluidic chip according to claim 6 or 7, characterized in that: After the second liquid insulator is injected into the sample injection port, the microfluidic chip is stored at a temperature lower than the melting point of the first liquid insulator.

9. The reagent pre-storage method for a microfluidic chip according to claim 6 or 7, characterized in that: When the microfluidic chip is used for detection, the second liquid insulator is heated and melted by a heater arranged directly below the liquid flow port.

10. The reagent pre-storage method for a microfluidic chip according to claim 9, characterized in that: After the second liquid insulator located at the liquid flow port is melted, an electrowetting process is performed on the electrode on the substrate to drive the reagent to move on the electrode.

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